Nifedipine and nicardipine are known compounds, as described in U.S. Pat. Nos. 3,644,627 and 3,985,758, respectively, that are analogous to the dihydropyridine derivatives of the present invention. These compounds are known to be useful as antihypertensive agents, peripheral and cerebral vasodilators, and as coronary vasodilators (administered for the treatment of angina pectoris). However, the advent of more efficacious dihydropyridine derivatives has been desired.